JSON之三：获取JSON文本并解释（以google的天气API为例）

google提供了天气的api，以广州天气为例，地址为：

http://api.openweathermap.org/data/2.5/weather?q=guangzhou

返回的结果为：

{
"coord": {
"lon": 113.25,
"lat": 23.12
},
"sys": {
"message": 0.2088,
"country": "CN",
"sunrise": 1400017567,
"sunset": 1400065233
},
"weather": [
{
"id": 501,
"main": "Rain",
"description": "moderate rain",
"icon": "10d"
}
],
"base": "cmc stations",
"main": {
"temp": 299.818,
"temp_min": 299.818,
"temp_max": 299.818,
"pressure": 1004.54,
"sea_level": 1014.72,
"grnd_level": 1004.54,
"humidity": 97
},
"wind": {
"speed": 4.42,
"deg": 201.501
},
"rain": {
"3h": 6
},
"clouds": {
"all": 44
},
"dt": 1400055192,
"id": 1809858,
"name": "Guangzhou",
"cod": 200
}

因此，在本范例中，写一个天气查询的DEMO，用于输入地点，并查询天气情况。

项目更新请见：https://code.csdn.net/jediael_lu/googleweatherparse/tree/master

效果如下：







详细步骤如下：

1、主界面布局文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="15dp"
android:text="@string/location"
android:textAppearance="?android:attr/textAppearanceMedium" />

<EditText
android:id="@+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/textView1"
android:layout_alignParentRight="true"
android:ems="10" />

<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView1"
android:layout_below="@+id/textView1"
android:layout_marginTop="68dp"
android:text="@string/country"
android:textAppearance="?android:attr/textAppearanceSmall" />

<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView2"
android:layout_marginTop="19dp"
android:text="@string/temperature"
android:textAppearance="?android:attr/textAppearanceSmall" />

<TextView
android:id="@+id/textView4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView3"
android:layout_below="@+id/textView3"
android:layout_marginTop="32dp"
android:text="@string/humidity"
android:textAppearance="?android:attr/textAppearanceSmall" />

<TextView
android:id="@+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/textView4"
android:layout_below="@+id/textView4"
android:layout_marginTop="21dp"
android:text="@string/pressure"
android:textAppearance="?android:attr/textAppearanceSmall" />

<EditText
android:id="@+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/textView3"
android:layout_toRightOf="@+id/textView3"
android:ems="10" >

<requestFocus />
</EditText>

<EditText
android:id="@+id/editText3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView3"
android:layout_alignBottom="@+id/textView3"
android:layout_alignLeft="@+id/editText2"
android:ems="10" />

<EditText
android:id="@+id/editText4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/textView5"
android:layout_alignLeft="@+id/editText1"
android:ems="10" />

<EditText
android:id="@+id/editText5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView5"
android:layout_alignBottom="@+id/textView5"
android:layout_alignRight="@+id/editText4"
android:ems="10" />

<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/editText2"
android:layout_below="@+id/editText1"
android:onClick="open"
android:text="@string/weather" />

</RelativeLayout>

2、定义String.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="app_name">JSONParser</string>
<string name="action_settings">Settings</string>
<string name="hello_world">Hello world!</string>
<string name="location">Location</string>
<string name="country">Country:</string>
<string name="temperature">Temperature:</string>
<string name="humidity">Humidity:</string>
<string name="pressure">Pressure:</string>
<string name="weather">Weather</string>
</resources>

3、在AndroidManifest.xml中添加internet访问权限。

4、创建一个bean，用于保存天气信息。

package com.example.jsonparser.model;

public class WeatherBean {

private String country;
private int Temperature;
private int humidity;
private int pressure;
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public int getTemperature() {
return Temperature;
}
public void setTemperature(int temperature) {
Temperature = temperature;
}
public int getHumidity() {
return humidity;
}
public void setHumidity(int humidity) {
this.humidity = humidity;
}
public int getPressure() {
return pressure;
}
public void setPressure(int pressure) {
this.pressure = pressure;
}

}

5、创建用于访问网络的类，并返回JSON文本。

package com.example.jsonparser;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class JSONFetcher {

private String jsonText = "";

//本方法通过指定url访问网络数据，并返回JSON格式的string。
public  String getJSONText(final URL url){

Thread thread = new Thread(new Runnable(){

@Override
public void run() {
InputStream is =null;
BufferedReader in = null;

try {
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(10000 /* milliseconds */);
conn.setConnectTimeout(15000 /* milliseconds */);
conn.setRequestMethod("GET");
conn.setDoInput(true);
conn.connect();

is = conn.getInputStream();
in = new BufferedReader(new InputStreamReader(is));
String line = "";
while((line = in.readLine()) != null){
jsonText += line;
}

} catch (IOException e) {
e.printStackTrace();
}finally{
try {
in.close();
is.close();
} catch (IOException e) {
e.printStackTrace();
}

}

}

});

thread.start();

//等待上述线程完成执行后再返回jsonText。
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}

return jsonText;
}

}

6、创建用于处理JSON文本的类，返回一个WeatherBean对象。

package com.example.jsonparser;

import java.net.URL;

import org.json.JSONException;
import org.json.JSONObject;

import com.example.jsonparser.model.WeatherBean;

public class JSONUtil {

public static WeatherBean getWeatherBean(URL url){

String jsonText = new JSONFetcher().getJSONText(url);
System.out.println(jsonText);
WeatherBean weather = new WeatherBean();

try {
JSONObject weatherJSONObject = new JSONObject(jsonText);

JSONObject sysJSONObject = weatherJSONObject.getJSONObject("sys");
String country = sysJSONObject.getString("country");
JSONObject mainJSONObject = weatherJSONObject.getJSONObject("main");
int temperature = mainJSONObject.getInt("temp");
int pressure = mainJSONObject.getInt("pressure");
int humidity = mainJSONObject.getInt("humidity");

weather.setCountry(country);
weather.setTemperature(temperature);
weather.setHumidity(humidity);
weather.setPressure(pressure);
} catch (JSONException e) {
System.out.println("test");
e.printStackTrace();
}

return weather;
}
}

7、主布局文件，将WeatherBean中的内容在手机中展现。

package com.example.jsonparser;

import java.net.URL;

import com.example.jsonparser.model.WeatherBean;

import android.os.Bundle;
import android.app.Activity;
import android.view.View;
import android.widget.EditText;

public class MainActivity extends Activity {

private String url1 = "http://api.openweathermap.org/data/2.5/weather?q=";
private EditText location, country, temperature, humidity, pressure;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
location = (EditText) findViewById(R.id.editText1);
country = (EditText) findViewById(R.id.editText2);
temperature = (EditText) findViewById(R.id.editText3);
humidity = (EditText) findViewById(R.id.editText4);
pressure = (EditText) findViewById(R.id.editText5);
}

public void open(View view) {

try {
URL url = new URL(url1 + location.getText().toString());
System.out.println(url);
WeatherBean weatherBean = JSONUtil.getWeatherBean(url);
country.setText(weatherBean.getCountry());
humidity.setText(weatherBean.getHumidity() + "");
pressure.setText(weatherBean.getPressure() + "");
temperature.setText(weatherBean.getTemperature() + "");
System.out.println("test2");

} catch (Exception e) {
e.printStackTrace();
}
}
}